趋流行为下斑马鱼幼鱼的全脑成像

目的 趋流，意即在水中调整身体方向并逆流而上的能力，是一种在大多数鱼类与两栖类动物中存在的保守行为。虽然关于趋流的研究已有一段很长的历史，并且近年来斑马鱼幼鱼趋流行为的理论机制也被提出，但是分布式的神经环路是如何整合多感知信息、做出决策、并实现行为控制仍然是个未知数。对自由运动的斑马鱼进行全脑神经活动成像为理解这一困难的问题提供了特殊的机会。方法 本文开发了一种微流控装置精确控制环境水流并激发斑马鱼的趋流行为。将该微流控芯片与扩增视野光场显微镜以及追踪系统整合，从而记录自由行为下斑马鱼全脑的神经活动。结果 在整合的微流控装置中稳定观察到了斑马鱼在水流中保持自身位置不变、逆流而上等刻板的趋流行为现象。与此同时，实现了对斑马鱼幼鱼趋流行为过程中的全脑钙活动记录。本文初步发现了几个脑区的神经活动与趋流行为相关。结论 本研究第一次展示了在斑马鱼幼鱼趋流行为的同时记录全脑神经活动的技术。接下来对神经活动和行为数据的分析与建模将有助于更好地理解一种重要自然行为背后的感觉运动转换机制。

Whole Brain Imaging of Larval Zebrafish during Rheotaxis

Objective Rheotaxis, namely to orient and swim against the water flow, is a conserved behavior across most fish and amphibians. While the study of rheotaxis behavior has a relatively long history, and in recent years the behavioral algorithm of rheotaxis has been described, how distributed neural circuits integrate multisensory information, make decisions, and generate counterflow motor sequences remain largely unknown. Whole brain calcium imaging of larval zebrafish during rheotaxis would provide a unique opportunity to tackle this difficult problem.Methods To this end, we developed a microfluidic device that can precisely control the water flow and elicit rheotaxis behavior. By integrating the chip with a customized light field tracking microscope, we built a system to record whole brain neural activity in freely behaving larval zebrafish during rheotaxis.Results Larval zebrafish showed reliable rheotaxis behavior in the setup, represented by prominent positional holding and counterflow swimming bouts in water flow. In the meanwhile, we successfully recorded zebrafish whole brain neural activity, from which a few brain regions were identified whose calcium signals strongly correlated with rheotaxis behavior.Conclusion Our study, for the first time, demonstrates a method for imaging whole brain neural activity in larval zebrafish while the animal is performing rheotaxis. Future analysis and modelling of the neural activity and behavioral data will deepen our understanding of sensorimotor transformation in this important naturalistic behavior.